A wireless communication system supports a sleep mode for minimizing power consumption of a terminal, and a terminal in the sleep mode repeats a sleep window and a listening window.
During the sleep window, the terminal saves power by not performing operation for data receiving. During the listening window, the terminal receives a message that informs generation of downlink traffic to be transmitted to the terminal during the sleep window from a base station, and when the downlink traffic is generated, the terminal terminates the sleep mode and changes to an awake mode to receive the downlink traffic from the base station.
The sleep mode is performed between a base station and each terminal. That is, the base station transmits a message that informs generation of downlink traffic to a corresponding terminal for each terminal in a sleep mode.
Since the base station transmits a message indicating generation of downlink traffic to each of terminals having similar sleep and listening windows, system overhead is increased and performance is deteriorated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.